‘Potentially harmful substance’ sent to U.S. military base in D.C.

Authorities are investigating whether a poisonous substance was sent to a U.S. military base in Washington, D.C., Senate Majority Leader Harry Reid said on Tuesday.

Reid told reporters there was "an alleged ricin incident" at Joint Base Anacostia-Bolling, which serves the Navy and Air Force and is located in the southeastern part of the city.

A spokesman for the Defense Intelligence Agency confirmed that a mail screening detected a "potentially harmful substance" at the base.

"This morning, DIA security personnel detected a potentially harmful substance during routine screening of incoming mail," DIA spokesman Lt. Col. Thomas F. Veale told Yahoo News in an email. "Tests by experts called in to assist indicate possible biological toxins. Prudent screening methods and force protection measures were implemented to prevent personnel from being harmed. DIA has maintained normal operations, and will not comment further on this event until an investigation is complete."

The news comes just days after letters were mailed to the offices of Mississippi Republican Sen. Roger Wicker, President Barack Obama and a Mississippi state judge that tested positive for ricin, which can be deadly if inhaled.

A suspect held in the investigations of the other ricin-laced letters, Paul Kevin Curtis, was released from custody earlier Tuesday. The investigation is still ongoing.